The invention relates to vehicle turn indicators, and more particularly to such indicators which, when actuated, provide an audible signal to the operator of the vehicle.
Third parties, whether drivers of other vehicles or pedestrians, tend to place considerable reliance on the validity of the external turn signals (usually flashing lights) emitted by a nearby vehicle for informing them of the path which that vehicle is intended to follow. If these external turn signals do not give a correct indication of that intended path, dangerous situations can arise which can readily result in serious accidents.
It is well-known that turn signals are conventionally turned "on" by the operator of a vehicle by placing a lever-actuated switch, usually mounted on the vehicle's steering column, into a detent corresponding to the direction of the intended turn. The turn signal is subsequently turned "off" automatically by a cam-operated mechanism, which restores the lever- actuated switch to the "off" position when the steering wheel rotates through a predetermined angle in the direction opposite to that signaled by the turn indicator. This automatic signal canceling technique is effective in most respects; however, it can inadvertently fail if the turning movement of the steering wheel, after the external signal has been turned on, is insufficient to enable the automatic cancellation mechanism to operate.
This can happen either because the vehicle operator decides not to make the signaled turn, after all, or because the turn was too shallow to enable the mechanism to function.
Conventionally, the turning on of external turn signals is accompanied by signals provided inside the vehicle to its operator. These take the form of a flashing light on the vehicle dashboard, accompanied by the "clicking" sound produced within the driver's seating area by the mechanism (usually a bi-metal electrical switch element) which causes the flashing of both the external and internal turn indicator lights.
It has been found that the functioning of these conventional internal signals is frequently inadequate to alert the vehicle operator to the fact that automatic cancellation of the external turn signals has not taken place as expected.
The flashing light on the dashboard is often insufficient because the vehicle operator's vision tends to be concentrated on the road, rather than on inside visual cues.
As for the clicking sound, this is often lost among other, more obtrusive sounds, such as traffic noise, conversations, radio playing, etc., or by its continuous and commonplace nature, it is simply overlooked.
Thus, it is common to see a vehicle travelling with its external turn signals flashing, but without making the indicated turn, even though the opportunity for doing so presents itself. Consequently, instead of giving a correct indication of the intended vehicle path, a misleading indication is provided.
This phenomenon is so prevalent that it has even been the butt of newspaper cartooning.
It has been proposed to overcome this shortcoming by installing a device which augments the clicking sounds emitted by the above-mentioned bi-metal flasher mechanism. Such a device is sold by the Ideal Division, Stant Corporation, St. Augustine, Fla., 32096, under the name "Loud Turn Signal Flasher", and the model designation 577V. The display card on which this device is mounted for sale states, inter alia, "Emits pulsing sound more than twice as loud as regular flashers to warn driver the turn signal is flashing. Replaces existing flasher unit."
While such a device tends to lessen the danger that the vehicle operator may simply fail to hear the turn indicator alerting sounds, it also introduces its own problems. The very loudness of the sound which it produces can, itself, be disturbing and may divert the vehicle operator from giving attention to other tasks required in the operation of the vehicle.
Also, the intrusiveness of this loud sound may actually discourage the operator from using the turn indicator, thereby creating its own potential for danger.